“Catastrophic” is the word several U.S. officials use privately to discuss the latest developments in Syria, in which a savage Russian bombing campaign has brought Aleppo near the point of surrender. Yet even as members of the Obama administration acknowledge the horror, they remain wary of options that might counter the onslaught.

Whatever else U.S. officials say about Syria, they should begin with an admission that we are diminished, as individuals and as a nation, by watching the destruction of a city and its people. Russia may be wading further into a military quagmire, but the United States is deep in a moral one. The stain of Syria won’t leave our national consciousness for many years.

U.S. intelligence officials describe a Russian campaign to break the Syrian opposition’s will, much as the United States and its allies did in the incendiary bombing of German and Japanese cities in World War II. Russian weapons now include thermobaric bombs, incendiary munitions, cluster bombs and bunker busters. They are attempting to burn Aleppo alive.

As cease-fire talks collapsed over the past two weeks, the Russians have struck hospitals, bread lines at bakeries, civilian neighborhoods. The message, says one U.S. analyst, is: “Surrender and you can eat again.”

Here’s a U.S. intelligence official’s chilling assessment: “The Syrian regime and its Russian backers have adopted a calculated approach of exacerbating the dire humanitarian situation in Aleppo as a weapon of war. Their apparent goal is to make living conditions in the city so intolerable that the opposition has no choice but to capitulate.”

Think about those dry analytical words: The Russians have made civilian suffering “a weapon of war.”

U.S. analysts fear that Aleppo may fall in a few weeks, marking a significant turning point in the war. The analysts note that the city could hold out several months longer, given residents’ resilience. I witnessed that spirit four years ago this month, when I visited Aleppo as it was being shelled, even then, by the regime. I stayed a few hours. The Syrian residents have remained for 48 months.

If Aleppo does fall, what then? The answer is a deeper, nastier civil war. Explains the U.S. intelligence official: “Even if the regime is able to eke out a victory in Aleppo, the opposition will not be easily defeated. They are simply too large to defeat.” The opposition force totals about 100,000, including fighters from the al-Qaeda affiliate Jabhat al-Nusra, analysts estimate. (The group said recently that it was changing its name to the Front for the Conquest of Syria and splitting from al-Qaeda.)

U.S. officials see two possibilities if Aleppo surrenders. Opposition fighters could disperse and harass Syrian and Russian troops behind the lines or they could concentrate forces in the rural areas of provinces such as Idlib, Homs, Hama and Daraa where the opposition is already strong. The United States and its coalition partners — such as Turkey, Jordan and Saudi Arabia — could increase covert military support to these fighters.

Backing the opposition is a tricky problem. A U.S. official says Jabhat al-Nusra has been the “main beneficiary” (other than the Assad regime) of Russia’s onslaught. “Until Moscow stops bombing hospitals and aid workers, Nusra will continue to exploit the situation . . . and portray itself as the defender of the Syrian people,” the official explained.

“What’s ahead is not regime control, but guerrilla warfare,” predicts one analyst. For Russia, that can’t be an appetizing prospect. That’s one reason U.S. officials are keeping the door open for Russia to return to the table — not in bilateral talks with the United States, which were suspended this week, but in a multilateral forum that might include Iran and Saudi Arabia.

White House caution about military options is reinforced by the Pentagon, as has been the case since the Syria conflict began. Pentagon officials still cite a 2013 letter from Gen. Martin Dempsey, then chairman of the Joint Chiefs of Staff, warning Congress that a no-fly zone to protect civilians would cost $500 million initially and $1 billion a month thereafter, and would “require hundreds of ground and sea-based aircraft.” The administration’s wariness has deepened since Russia’s intervention in 2015.

If military options are risky in Aleppo, what about humanitarian assistance? Here, there’s an opportunity for America to be bold — in a massive mobilization, organized as quickly as hurricane or earthquake relief, that could bring aid to suffering civilians.

Line the relief convoys up at the Turkish, Jordanian and Lebanese borders and dare the Russians to stop them. Air-drop supplies to a besieged, desperate city. Let the world see what Russia’s brutal policies have brought. These are inadequate, imperfect options, but they’re surely better than doing nothing.